Pump or motor having four cylinders arranged in one plane



ONE PLANE E. WOYDT PUMP 0R MOTOR HAVING FOUR CYLINDERS ARRANGED IN Filed June 4. 1956 2 Sheets-Sheet l INV'NTOIP E E0 9031;

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a 5 f H w I I .VIIHH United States Patent PUMP OR MOTOR HAVING FOUR CYLINDERS GED IN ONE PLANE Eduard Woydt, Stuttgart, Germany Application June 4, 1956, Serial No. 589,161 Claims priority, application Germany July 25, 1955 14 Claims. (Cl. 103-169) Liquid pumps or motors having four cylinders arranged in one plane are known, in which the inlets and outlets of every cylinder are controlled by the piston of an adjacent cylinder, the said piston being in the form of a controlling slide valve (see German Patent No. 888,206). These known machines always require more or less long connecting pipes from the working chamber of one cylinder to that place of the other cylinder at which the control is effected by the distributing slide-valve type of piston. Owing to this the clearance becomes greater than is permissible with pumps having a variable stroke, so that the efiiciency is also had. Particularly in hydrostatic gears is the large clearance a disadvantage.

The object of the invention is to reduce the size of the clearance, and consists in the fact that the working chamber of each cylinder opens 'frontally into that cylinder, in which the piston controlling it travels. In this way the axes of the cylinders can form a rectangle, for example, a square. The inlet and outlet ducts of all the cylinders are preferably connected to a common central piping, the outlet and inlet ducts of all the cylinders being connected to an annular pipe.

A further object of the invention is the attainment of a simple method of construction of pumps with infinitely variable control of the delivery quantity so that the control thereof can be carried out in the most simple and precise manner possible. The invention also refers therefore to the drive and the means for the infinitely variable adjustment of the control of the four cylinders, whose axes form a square.

The drawing illustrates one embodiment of a liquid pump, wherein:

Figure 1 is a cross-section through a liquid pump sub stantially along the line I-I of Figures 2 and 3, in which however individual parts are shown in crosssection.

Figure 2 shows in its upper part (within the housing ring 23) a cross-section along IIII of Figure 1, and

Figure 3 is a cross-section along IIIIII of Figure 1, through that part which (at the top in Figure 2) is surrounded by the plates 9 and as well as the housing ring 23, while the housing 24 with the parts arranged in it is here omitted.

Moving in suitable cylindrical bores in square cylinder block 1 (Figure 1) are four pistons 2a, 2b, 2c, 2d, which control annular inlet channels 3a and annular outlet channels 4a by their neck portions 6 or the control edges 6a and 6b (as has been shown and described in the US. patent application No. 500,258 of April 8, 1955, and the British patent application Ser. No. 3,134 of March 21, 1955). The outlet grooves 4a are :ach connected through a bore 4 to a common outlet ripe 5, while the inlet grooves 3a, through bores 3 passng through a rear plate 9, terminate in a common inlet :hannel 7 into which opens an inlet pipe 8. The workng chamber of every cylinder opens at the end into that :ylinder in which the piston controlling it is adapted to ravel. The axes of the cylinders or of the pistons form rectangle, and in fact a square (Figure 1). The cyla substantially 14a, are also mounted in inder block 1 is secured to the plates 9 and 10 by means of screws 1a. Mounted in the two plates 9 and 10 are two triple-cranked crankshafts 13 with two crankpins 13a and one crankpin 13b (Figure 3). Two singlecranked crankshafts 14 (Figure 2), each with a crankpin the same way. Each of the pistons 2a, 2b, 2c, 2d carries two-armed levers 16a, 16b, 16c, 16d which are adapted to pivot about journals 15. Fork-shaped ends 17 of each of these levers are connected by means of trunnions 17a to connecting rods 18, which in their turn engage the crankpins 14a, or 13b. The other ends 19 of the levers 16a, 16b, 16c, 16d carry journals 20, on which are rotatably mounted short connecting rods 21, the other ends of which engage the crankpins 14a and 13a.

The space between the two plates 9 and 10 is closed by a housing ring 23 (with a base 23a for erection of the pump), while a housing 24 is flanged to the plate 10 at 24a. The driving shaft 25 of the pump is mounted in the plate 10 and in the wall of the housing 24. Rigidly carried by the shaft 25 is a gearwheel 26, meshing with which are two pinions 27, which are seated on the crankshafts 14. In addition, a sleeve 28 is mounted on the shaft 25 so as to be longitudinally movable (arrow 31), but not rotatable. The sleeve is formed with longitudinal grooves 29 engaged by keys 30, which are fast with the shaft 25. The sleeve 28 is formed externally with keys 32 extending in the manner of a steep thread; rotatable thereon is the hub 33a of a wheel 33, which is not movable axially with respect to the gearwheel 26 and the shaft 25, since arms 34 fixed to the gearwheel 26 engage in an annular groove 35 of the hub 33a. When the sleeve 28 is reciprocated axially, the wheel 33 turns to the right or left with respect to the toothed wheel 26 and the shaft 25. The extent of the turning moving depends on the pitch of the thread-like keys 32. The wheel 33 has internal teeth 33b engaged by two pinions 36, each of which is seated on a crankshaft 13.

If the shaft 25 is turned in a clockwise direction then through the toothed wheel 26 and the pinions 27 it turns the crankshafts 14 in a counter-clockwise direction, while the crankshaft 13 is turned clockwise through the toothed wheel 33 with internal teeth 33b as well as through the pinions 36. As the radii of the crankpins 13a, 13b and 14a are of the same size and as moreover the spacing 15, 17a at the levers 16a, 16b, 16c and 16d are equal to the spacings 15, 20, the journals 15 and with them the pistons 2a, 2b, 2c, 2d, travel distances which are equal to twice the radius of the crankpins 13a, 13b or 14a. However, if the angular position of the crankshaft 13 relatively to the crankshafts 14 is changed, then the path traversed by the journals 15 and the pistons becomes smaller. If the angular position of the crankshafts 13 relatively to the crankshafts 14 reaches the value of the movement of the journals 15 and the pistons becomes equal to zero,

so that then the levers 16a, 16b, 16c and 16d only rock backwards and forwards about the journals 15. The angular adjustment is effected by moving the sleeve 28, as described above. The movements of the pistons can therefore be infinitely adjusted from a maximum (which is reached in the position in the drawing) down to zero, so that the capacity of the pump is also variable between zero and the maximum.

It is of course possible for several cylinder blocks 1 with plates 9 and 10 to be juxtaposed. The crankshafts 13 and 14 can therefore simultaneously actuate pistons of several cylinder blocks, if they are of suitable design. In this way pumps can be produced with four, eight or twelve cylinders.

The arrangement in accordance with the invention can also be employed to advantage, irrespective of whether the cylinder block 1 rotates or is stationary. Arrangements with rotating cylinder blocks are especially indicated for the construction of gears, i.e., with such machine assemblies in which a pump of the type shown is coupled to a hydraulic motor of similar type for the purpose of infinitely variable adjustment of a drive, for example motor vehicles.

By the use of the connecting rods 18, 21 of difierent length and by the alternating arrangements of single and double cranked crankshafts 13, 14, it is possible for the driving shaft 25 to be positioned symmetrically of the pistons or cylinders.

The construction obtained according to the invention is relatively small owing to the use of a rectangular cylinder block 1. Due to the two side walls 9, 10, a complicated pump or motor housing is dispensed with, so that the construction in accordance with the constructional example is more simple and less costly than the known methods of construction of motors and pumps for liquids with high pressure and variable stroke. As compared with known pumps or motors with radially arranged cylinders, the elimination of members, especially springs, for the return movement of the pistons is of noticeable advantage. Owing to this, the engine speed can be considerably increased.

I claim:

1. Pump or motor for fluid including a block, at least four cylinder wall forming bores in said block dcfining cylinders with each cylinder having a head end within said block and having its head end intersecting an adjacent cylinder, a piston in each cylinder, ports forming an inlet and an outlet for each cylinder located in the wall of said adjacent cylinder, the inlet and outlet of each cylinder being controlled by the piston of said adjacent cylinder, each said piston being constructed at a point behind its operating face with a passage, whereby said piston operates as a controlling slide valve.

2. The pump or motor of claim 1, including a plurality of crank shafts, a common driving shaft operatively connected to said crank shafts, the pistons being each actuated by a lever arm connected at two spaced points by a connecting rod driven by a crank on a first and a second of said crank shafts from said cranks to said lever arm, one of said crank and connecting rod means connected to each said lever arm being angularly adjustble with respect to the other while the device is in operation to change the stroke of said pistons.

3. Pump or motor according to claim 1, characterized in that the axes of the cylinders and pistons are arranged to form a square.

4. The pump or motor of claim 1, including four lever arms and in which each piston is connected to the center of one of said lever arms, four crank shafts arranged each adjacent ends of two said lever arms, connecting rods operatively connecting each said crank shaft to two said adjacent ends of said lever arms, whereby rotation of said crank shafts causes a reciprocatory motion of said pistons in said cylinders, and common means to simultaneously drive said four crank shafts.

5. The pump or motor of claim 4, in which means are provided on said common means to simultaneously drive said crank shafts whereby two of said crank shafts may be adjusted angularly with respect to the other two of said crank shafts whereby the length of strokes of said pistons may be varied.

6. The pump or motor according to claim 5, in which said crank shafts are arranged about a circle, and said common driving means is a rotatable shaft having its axis at the center of said circle, two gears carried by said rotatable shaft, a pinion gear on each two alternate crank shafts meshing with one said gear, and a pinion gear on each of the other two crank shafts meshing with the other said gear.

7. The pump or motor according to claim 6, in which one of the two gears is secured fast to said rotatable shaft,

while the second gear is arranged on the rotatable shaft so as to be axially non-displaceable, but rotatable on said shaft, and means to rotate said second gear with respect to said shaft.

8. The pump or motor according to claim 7, in which the second gear is provided with threaded keys, a threaded sleeve non-rotatable but displaceably mounted on the shaft, said threaded keys and threaded sleeve inter.-

fitting whereby axial movement of said sleeve rotates said second gear With respect to said first gear.

9. The pump or motor of claim 3, in which four crank shafts are provided, two alternate crank shafts being rotatable together with respect to said other two crank shafts, a lever arm mounted on said piston and connecting rods connecting to each crank shaft and to one end of each two adjacent levers, whereby each piston is operated by two crank shafts jointly and each crank shaft operates two pistons.

10. The pump or motor according to claim 9, in which the axes of each two crank shafts are at equal distances from the longitudinal axis of the piston jointly operated by them.

11. The pump or motor according to claim 9, in which a connecting rod operating each of two adjacent pistons is connected at the same angle to two crank shafts while the connecting rods of two adjacent pistons are connected with a displacement of to the other two crank shafts, the first-mentioned crank shafts rotating in a direction opposite to that of the two said crank shafts.

12. In a fluid handling mechanism, a cylinder block, a plurality of cylinder bores in said block, each said bore defining a cylinder having a head end within said block, its head end intersecting one of, and being intersected by the head end of another of said bores, an inlet and an outlet port for each said other of said bores in each said bore adjacent the head end of said other of said bore, a combination piston and valve means slidably mounted in each said bore, said piston and valve means each operating as a piston in the bore in which it slides and having a reduced portion lying generally opposite the point where the bore is intersected by said other bore, to operate as a valve to control the inlet and outlet ports for said other bore.

13. In a fluid handling mechanism, a cylinder block, a plurality of cylinder bores in said block each said bore defining a cylinder having a head end within said block, its head end intersecting one of and being intersected by the head end of another of said bores, combination piston and valve means slidably received in each said bore, each said piston being provided with a reduced valve forming portion to lie generally at the point where said bore is intersected by the head end of said other bore, an inlet and an outlet port in each said cylinder adjacent the point of intersection of said other bore, and common means to reciprocate each piston and valve means in its bore in timed relation with the other piston and valve means whereby each piston and valve means operates as a piston in the cylinder bore in which it slides and as a valve for the intersecting cylinder.

14. In a device of the character described, a cylinder block, a plurality of bores in said block forming operating cylinders, a piston in each of said cylinders, each said piston being provided with a portion of reduced area forming a valve passage, an inlet and an outlet port spaced longitudinally of each said cylinders so as to be alternately covered and uncovered by said valve passage upon movement of said piston in said cylinder, said cylinders being so located that each cylinder intersects an adjacent cylinder between said inlet and outlet ports, and means to operate said pistons in timed relation with each other so that each piston operates as a valve serving the intersecting cylinder.

(References on following page) 6 References Cited in the file of this patent 2,131,729 Fee Oct. 4, 1938 UNITED STATES PATENTS 2,471,195 Christopher May 24, 1949 1,109,349 Mealey Sept. 1, 1914 FOREIGN PATENTS 1,122,124 Johnsen Dec. 22, 1914 2,040,401 Persons May 12, 1936 5 915,525 Germany July 22, 1954 

